Many medical procedures require access into the vascular system of the patient. Although various means may be used to obtain access into a vein or artery, typically access is obtained by inserting a cannula or introducer sheath through the skin and into the selected blood vessel. A medical device or diagnostic instrument, such as a guide wire, guiding catheter, balloon angioplasty device, atherectomy device, or the like is then inserted into the vascular system through the cannula or introducer sheath.
In percutaneous transluminal coronary angioplasty, for example, it is customary to introduce a catheter into the femoral artery at an entry site in a patient's leg and to advance the catheter through the artery to the coronary region. The artery, which may be located one half inch or more beneath the skin, is punctured with a needle or similar device. A guide wire is inserted through the needle and the needle is removed. An introducer sheath and dilator together are threaded over the guide wire. The introducer sheath is often twisted and otherwise manipulated as it is inserted into the vessel, thereby causing further enlargement of the vascular puncture. The dilator is then removed and the catheter is inserted.
To permit the insertion of a medical device or instrument therethrough, the introducer sheath must be of a relatively large diameter. Introducer sheaths typically have a diameter in the range between one millimeter and six millimeters, thus creating a significant puncture in the artery. After the intravascular medical procedure is completed, this puncture must be closed and bleeding from the blood vessel stopped.
At present, such bleeding is stopped by the application of direct digital pressure over the puncture site by a trained physician or other suitably trained medical personnel. Such direct pressure must be applied for a sufficiently long time for hemostasis to occur so that the opening is effectively closed and further bleeding is prevented. In the case of punctures into the femoral artery, the pressure is generally applied for twenty to thirty minutes, but it may be necessary to apply pressure for as long as one hour. Further, twelve pound sandbags may then be placed on the puncture site for an additional two to six hours.
The time required to stop bleeding using digital pressure is not an efficient use of medical professional services. Not only is this direct digital pressure application procedure wasteful of time by highly skilled medical professionals, the procedure results in a substantial reduction, if not virtual arrest, of blood flow through the vessel. Since thrombosis is one of the major problems that can occur in the immediate post-operative period, any reduction in blood flow, caused by the application of digital pressure, is undesirable. Furthermore, when digital pressure is applied, an undesirable bruise or hematoma can form at the entry site, since internal bleeding of the punctured artery continues until clotting blocks the puncture. There is also a significant chance that upon movement by the patient, the puncture will reopen and begin bleeding again, resulting in a hematoma or other complications. In addition, when anticoagulants used in the medical procedure are left active in the body, the introducer sheath is generally left inside the patient for twelve to twenty four hours in order for the anticoagulants to clear from the blood. Because the patient may be required to remain immobile and because of the risk of complications, patients are usually required to remain overnight in the hospital for observation, thus greatly increasing the cost of the overall procedure.
One prior device for stopping bleeding from a puncture in a blood vessel is a type of expandable plug. An example of such a device is shown in U.S. Pat. No. 4,890,612 (Kensey). The plug is pushed through the puncture into the blood vessel and into the blood stream. Once exposed to blood, it expands. The expanded plug is then pulled back against the puncture where, because of its expanded size, it plugs the opening. A similar device is an expandable closure, such as that described in U.S. Pat. No. 4,852,568 (Kensey). Such devices may work satisfactorily, but require inserting and leaving a foreign object in the vessel for a period of time. It is usually medically preferable to avoid leaving objects in a vessel, even if they eventually biodegrade.
Another device for stopping bleeding from a puncture is disclosed in U.S. Pat. No. 4,929,246 (Sinofsky). This patent relates to a method for closing an artery using laser energy while simultaneously applying pressure directly to the artery through the use of a balloon placed on the exterior of the artery over the puncture site.